Chevrolet 1973 Monte Carlo Owner's Manual page 53

leaded or low-lead gasolines are
not available, gasolines containing
more than 0.5 grams per gallon
may be used.
In states using the Gasoline Per-
formance and Information System
of fuel designation, unleaded or
low-lead fuels having an anti-knock
designation of "2" or higher are
recommended.
Gas Cap-The fuel tank filler cap
has a new two-step removal and
installation procedure plus a
pressure-vacuum safety relief.
valve. It is equipped with a double
set of locking tangs. To remove:
• Rotate cap one-half tum coun-
terclockwise to clear the first set
of tangs from the slots inside
the filler neck. This, will allow
any residual pressure to escape.
• Pull the cap outward and rotate
one-quarter tum counterclock-
wise to clear second set of tangs
and remove the cap.
• To install, reverse this pro-
cedure.
NOTE: If this cap requires a re-
placement, only a cap with these
same features should be used. Fail-
ure to use the correct cap can
result in a serious malfunction of
the system. Correct replacement
caps may be obtained from your
authorized Chevrolet Dealer.
Engine Oil and Filter
Recommendations
• Use only SE engine oil.
• Change oil each 4 months or
6,000 miles. If more than 6,000
miles are driven in a 4-month
period, change oil each 6,000
miles.
• Change oil each 2 months or
3,000 miles, whichever occurs
51
first, under the following con-
ditions:
- driving in dusty conditions
- trailer pulling
- extensive idling
- short-trip operation at freez-
ing temperatures (engine not
thoroughly warmed-up).
• Operation in dust storms may
require an immediate oil change.
• Replace the oil filter at the first
oil change, and every second oil
change thereafter. AC oil filters
provide excellent engine pro-
tection.
See your Chevrolet dealer for
advice on the frequency of oil and
filter changes under unusual driv-
ing conditions.
The above recommendations
apply to the first change as well as
subsequent oil changes. The oil
change interval for your Monte
Carlo engine is based on the use of